The present invention relates to bicycle frames, and specifically to bicycle frames and front fork assemblies.
Bicycles commonly have a frame comprising a main frame and a rear triangle. The main frame is typically made from a top tube, a head tube, a down tube, and a seat tube, and the rear triangle is typically made from two chainstays and two seatstays. A front fork is commonly rotationally mounted in the head tube and is secured to handlebars for steering the bicycle. The frame and fork assembly is supported on a front wheel rotationally secured to the fork and a rear wheel rotationally secured to the rear triangle.
Additionally, prior art front fork assemblies 135a require added material to provide lateral stiffness, thereby increasing the weight. Referring to FIG. 9, prior art front fork assemblies 135a have a sharp radius at a juncture between a fork crown 140a and the steerer tube 137a. The steerer tube 137a projects from the fork crown 140a, and has a generally constant width. In order to provide structural strength to prior art front fork assemblies 135a, material is added to the connection between fork legs 145a and the fork crown 140a and between the fork crown 140a and the steerer tube 137a. Thus there is a direct correlation between the amount of lateral stiffness available in prior art front fork assemblies 135a and the amount of material that can be added to these connection points. The added material increases the weight of prior art front fork assemblies 140a, and the amount of stiffness that can be added is limited by the diameter of the tubes used for the front fork legs 145a, the fork crown 140a and the steerer tube 137a. 